if the neck snapped the hen felt no pain and was in a sense dead. even with out the head (cleanly removed from body by axe) the head will gasp and the body will move for a while. its just the way it is as the body still has impulses running through it. I have had culling go bad though and understand, it will haunt you for a few days, but try not to think about it and after a while you wont as much. but I promise the first time you wrung its neck it was gone and felt no pain.